Improve `generate_weblogo` modularity.
Improve `generate_weblogo` modularity.

- Take as an argument now the frequencies file.
- Create an optional `debug` argument to write the transfac file

jbarnoud/PBxplore,HubLot/PBxplore,pierrepo/PBxplore,jbarnoud/PBxplore,pierrepo/PBxplore,HubLot/PBxplore